Starting root finding/paving for interval arithmetic

toastedcrumpets · Jul 30, 2021 · edb2695 · edb2695
1 parent 9e512ef
commit edb2695
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Showing 4 changed files with 30 additions and 3 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,4 +1,7 @@
 cmake_minimum_required (VERSION 3.0)
+
+#set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/CMake/")
+
 if (NOT CMAKE_BUILD_TYPE)
   message(STATUS "No build type selected, default to Release")
   set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Choose the type of build, options are: Debug Release RelWithDebInfo" FORCE)
@@ -171,6 +174,7 @@ if(GTest_FOUND)
   stator_test(symbolic_numeric_test)
   stator_test(symbolic_parser_test)
   stator_test(symbolic_ad_test)
+
   stator_test(symbolic_interval_test)
   #stator_test(symbolic_integration_test)
 else()

diff --git a/README.md b/README.md
@@ -43,6 +43,11 @@ print(derivative(funcs, x)) # [0, 1, 4*x/4, 18*x^2/36, cos x, 0]
 print(sub(funcs, {x:1, Expr('y'): 2})) # [1.0, 1.0, 0.5, 0.16666666666666666, 0.8414709848078965, 0.9092974268256817]
 ```
 
+# Requirements
+
+You need the Google test library to build the unit tests. The Boost
+interval library is needed for interval arithmetic support.
+
 # Alternatives/Similar software 
 
 For the compile-time C++ library:
@@ -58,3 +63,7 @@ For the python bindings:
 - [sympy](https://www.sympy.org/): The full-featured CAS for python, but also quite slow.
 - [symengine](https://symengine.org/index.html): Just like
   stator. It's actually a C++ CAS engine with python wrappers.
+
+For the interval arithmetic
+- [Kodiak](https://github.com/nasa/Kodiak) This is a full library for interval arithmatic solving.
+- [Julia](https://github.com/JuliaIntervals/IntervalArithmetic.jl) A brilliant implementation of interval solving.
diff --git a/stator/symbolic/interval.hpp b/stator/symbolic/interval.hpp
@@ -1,7 +1,8 @@
-#include <boost/numeric/interval.hpp>
+#include <stator/symbolic/symbolic.hpp>
+#include <boost/numeric/interval.hpp> //filib++
 
 namespace sym {
-  using boost::numeric::interval;  
+  using boost::numeric::interval;
 
   template<class Config = DefaultReprConfig, class ...Args>
   inline std::string repr(const sym::interval<Args...>& f)

diff --git a/tests/symbolic_interval_test.cpp b/tests/symbolic_interval_test.cpp
@@ -18,7 +18,6 @@
 */
 
 //stator
-#include <stator/symbolic/symbolic.hpp>
 #include <stator/symbolic/interval.hpp>
 #define UNIT_TEST_SUITE_NAME Symbolic_
 #define UNIT_TEST_GOOGLE
@@ -27,6 +26,7 @@
 static constexpr char x_str[] = "x";
 static constexpr char y_str[] = "y";
 
+
 UNIT_TEST( symbolic_interval_basic ) {
   sym::interval<double> i1(0, 2);
   auto out = i1 * i1 - 2.0 * i1 + 1.0;
@@ -45,3 +45,16 @@ UNIT_TEST( symbolic_interval_basic ) {
 
   UNIT_TEST_CHECK_EQUAL(sym::repr(out), "-3...5");
 }
+
+template<class F, class X>
+auto root_find(const F& f, const X& x, const sym::interval<double>& range) {
+  return sym::interval<double>(0.0, 0.0);
+}
+
+UNIT_TEST( symbolic_interval_root ) {
+  sym::Var<x_str> x;
+
+  auto f = x * x - 2.0 * x + 1.0;
+
+  auto res = root_find(f, x, sym::interval<double>(0.0, 0.0));
+}